I've been having a little fettle with the mixte, not too much because I'm not sure if I want to get that
into it, but I pumped up the tyres to see if they would keep air, the rear did and the front did enough for me to ride it down the street and back, the gears work, the brakes work, the pedals turn etc. It defo needs a new back wheel and defo needs new tubes and tyres
Most of the rust is coming off with some GT85 and fine wire wool, I measured the chain and although it's rusty it hasn't stretched much, it could be salvageable. I removed the rear rack, that my be too far gone, but we shall see.
I'm puzzled by the size, it does feel to small for me though the measurement from the BB to the top of the seat tube is 56 the same as my modern carbon road bike, maybe the top tube is too short, I don't understand these things. Perhaps someone could explain that?
Some more photos.